As a wind power generation apparatus, an apparatus is known which is equipped with a blade that is rotated by receiving wind power; a main spindle connected to the blade; a speed increaser for increasing the rotation of the main spindle, and a generator including an input shaft that is connected to the output shaft of the speed increaser via a joint member. In this wind power generation apparatus, the blade receives wind power and the main spindle is rotated, the rotation of the main spindle is increased by the speed increaser to drive the generator, whereby electric power is generated. In the following explanation in this description, wind power means wind power received by the blade.
In this kind of wind power generation apparatus, when wind changes in speed and direction and wind power lowers, the rotation of the output shaft of the speed increaser is decreased, and this decreased rotation is transmitted to the input shaft of the generator via the joint member. Hence, the rotation of the input shaft of the generator is decreased. Thus, the output of the generator is lowered, thereby causing a problem of poor power generation efficiency. In order to solve this problem, the inventors of this application have already proposed an invention in which a one-way clutch is provided for the joint member (refer to Patent Document 1).
This one-way clutch is used so that when the rotation speed of the output shaft of the speed increaser is higher than the rotation speed of the input shaft of the generator, the input shaft and the output shaft are connected to each other so as to be rotatable integrally and so that when the rotation speed of the output shaft is lower than the rotation speed of the input shaft, the connection between the output shaft and the input shaft is released. Furthermore, in the case that wind power lowers and the rotation speed of the output shaft of the speed increaser is decreased, the connection between the output shaft and the input shaft of the generator is released by the one-way clutch, whereby the rotation of the input shaft of the generator is not decreased abruptly but the input shaft can be continuously rotated by the inertia of the heavy rotor of the generator, and the average rotation speed of the input shaft is increased and power generation efficiency is improved.